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PET Packaging Insights

PET Preform Weight Guide: Matching Gram Weight to Bottle Volume

Preform gram weight is the single biggest driver of both bottle performance and resin cost. Pick it well and you balance top-load, burst resistance and material spend; pick it badly and you over-stretch the wall or waste PET on every shot.

Weight follows volume — and application

As bottle volume grows, the preform must carry more material to keep an even, blow-able wall. Delta El Nile for Industry’s public range runs from a 9 g 330 ml water preform to a 668.5 g 19 L returnable Co-PET preform. Carbonated drinks (CSD) sit heavier than still water at the same volume because the wall must hold CO₂ pressure.

Weight range by application

Delta El Nile for Industry’s public catalogue maps each application to a weight band, neck finish and resin grade:

ApplicationBottle volumeWeight rangeNeck finishResin IV / AA
Water330 ml – 19 L9 – 668.5 g29/25 · 48 mm · 55 mm0.76–0.80 dl/g · AA <6 ppm
Carbonated (CSD)250 ml – 2.5 L13 – 53.6 gPCO 1881 · PCO 18100.84 dl/g · AA <10 ppm
Edible oil750 ml – 5 L17.6 – 84 g29/21 · 42/360.84 dl/g · AA <10 ppm
Juice & milk250 ml – 1.25 L11 – 32 g32/15 · 38 mm0.76–0.80 dl/g · AA <6 ppm

5-gallon / 19 L returnables run a higher IV band (0.84–0.87 dl/g). Browse every weight in the Product Catalog, or filter by application, neck and volume in the Product Finder.

The lightweighting trade-off

Lightweighting lowers cost and carbon, but every gram removed raises the stretch ratio. Past a point you lose top-load and risk stress-whitening. Validate any aggressive weight against the bottle geometry before committing.

Worked example

For a 600 ml still-water bottle on a 29/25 neck, the catalogue weight is DEN-WATER-12-29-25 (12 g). Stepping down to 10.5 g is possible on a shorter bottle but raises the stretch ratio — confirm before quoting.

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